Bash - Multiple replace with sed statement - bash

Question

I'm getting mad with a script performance.
Basically I have to replace 600 strings in more than 35000 files.
I have got something like this:
patterns=(
oldText1 newText1
oldText2 newText2
oldText3 newText3
)
pattern_count=${#patterns[*]}
files=(`find \. -name '*.js'`);
files_count=${#files[*]}
for ((i=0; i < $pattern_count ; i=i+2)); do
search=${patterns[i]};
replace=${patterns[i+1]};
echo -en "\e[0K\r Status "$proggress"%. Iteration: "$i" of " $pattern_count;
for ((j=0; j < $files_count; j++)); do
command sed -i s#$search#$replace#g ${files[j]};
proggress=$(($i*100/$files_count));
echo -en "\e[0K\r Inside the second loop: " $proggress"%. File: "$j" of "$files_count;
done
proggress=$(($i*100/$pattern_count));
echo -en "\e[0K\r Status "$proggress"%. Iteration: "$i" of " $pattern_count;
done
But this takes tons of minutes. There is another solution? Probably using sed just one time and not in a double loop?
Thanks a lot.

Answer 1

Create a proper sed script:
s/pattern1/replacement1/g
s/pattern2/replacement2/g
...
Run this script with sed -f script.sed file (or in whatever way is required).
You may create that sed script using your array:
printf 's/%s/%s/g\n' "${patterns[#]}" >script.sed
Applying it to the files:
find . -type f -name '*.js' -exec sed -i -f script.sed {} ';'
I don't quite know how GNU sed (which I assume you're using) is handling multiple files when you use -i, but you may also want to try
find . -type f -name '*.js' -exec sed -i -f script.sed {} +
which may potentially be much more efficient (executing as few sed commands as possible). As always, test on data that you can afford to throw away after testing.
For more information about using -exec with find, see https://unix.stackexchange.com/questions/389705

Answer 2

You don't need to run sed multiple times over one file. You can separate sed commands with ';'
You can execute multiple seds in parallel
For example:
patterns=(
oldText1 newText1
oldText2 newText2
oldText3 newText3
)
// construct sed argument such as 's/old/new/g;s/old2/new2/g;...'
sedarg=$(
for ((i = 0; i < ${#patterns[#]}; i += 2)); do
echo -n "s/${patterns[i]}/${patterns[i+1]}/g;"
done
)
// find all files named '*.js' and pass them to args with zero as separator
// xargs will parse them:
// -0 use zero as separator
// --verbose will print the line before execution (ie. sed -i .... file)
// -n1 pass one argument/one line to one sed
// -P8 run 8 seds simulteneusly (experiment with that value, depends on how fast your cpu and harddrive is)
find . -type f -name '*.js' -print0 | xargs -0 --verbose -n1 -P8 sed -i "$sedarg"
If you need the progress bar so much, I guess you can count the lines xargs --verbose returns or better use parallel --bar, see this post.